Sub-caliber projectile and method of neutralizing a target using such a projectile

ABSTRACT

A sub-caliber projectile of the kinetic energy type comprising a perforating rod surrounded by a sabot made of light material and allowing the projectile to be fired from a weapon, the rod being extended by a stabilizing tail. The tail is connected to the rod by a connection means that can be broken, the breaking being initiated by a control means integral with the projectile. The control means comprises a timing module which is connected to a programming interface and which is programmed before firing or during firing so as to ensure the breaking of the connection means at a reference distance relative to a target which is to be neutralized. The invention also relates to a method of neutralizing a target using such a sub-caliber projectile.

The technical field of the invention is that of sub-caliber projectiles and in particular sub-caliber projectiles of the large-caliber kinetic energy penetrator type (caliber greater than 75 mm).

Sub-caliber projectiles (or kinetic energy projectiles) are well known. They consist of a rod of perforating material, with a conical front part, and carrying a stabilizing tail.

The rod is of a much smaller caliber than that of the weapon firing the projectile (a rod of 25 to 30 mm in diameter for a weapon caliber of 120 mm).

Firing is made possible thanks to a sabot of the same caliber as the weapon, which releases the rod at the exit of the barrel of the weapon.

This conventional configuration allows a particularly high rod speed (of the order of 1700 meters per second for a kinetic energy rod fired by a 120 mm caliber weapon) to be obtained. Patents U.S. Pat. No. 4,724,769 and FR2842897 describe known kinetic energy projectiles as examples.

The high velocity imparted to them, as well as the mass of the rod, give the rods a very high capacity to perforate armor.

However, the rods of the arrows are nowadays confronted with active protection systems which act by blast effect. Vehicles equipped with such protection systems thus project a grenade incorporating a thermobaric explosive towards the rod.

The intense blast generated by such a grenade will act on the kinetic projectile and deflect it from its trajectory, thus reducing its perforating effectiveness.

The action of these thermobaric grenades is essentially exerted on the tail of the kinetic energy projectile, the span of which is practically triple the caliber of the rod.

The patent FR2390703 also describes a sub-caliber practice projectile whose tail is ejected on a trajectory, at a fixed moment shortly after firing, in order to reduce the trajectory of the projectile. This projectile has a very shortened trajectory (of the order of a few hundred meters) compared to the trajectory of a perforating projectile (greater than 6500 meters). This projectile is not designed to have target perforating performance and is unsuitable for solving the problem at hand.

Such a sub-caliber practice projectile in which the tail is separated from the rod on a trajectory is also described in patent US2002/0088897.

Patent DE3933442 describes a perforating projectile whose tail separates from the rod on impact with a target. The aim is to prevent the tail from reducing the perforation of the target.

Such a projectile is disrupted by blast grenades. It cannot solve the problem of the resistance of the projectile to thermobaric protections.

It is the object of the invention to propose a sub-caliber projectile which is not or only slightly disrupted by modern blast protection.

The invention also proposes a method for neutralizing a target using such a projectile.

Thus, the object of the invention is a sub-caliber projectile of the kinetic energy type, comprising a perforating rod surrounded by a sabot made of light material and allowing the sub-caliber projectile to be fired from a weapon, the rod being extended by a stabilizing tail, the stabilizing tail being connected to the rod by a connection means which can be broken, breaking of the connection means being initiated by a control means integral with the sub-caliber projectile, wherein the control means comprises a timing module which is connected to a programming interface and which is programmed before firing or during firing so as to ensure breaking of the connection means at a reference distance relative to a target which is to be neutralized.

According to a particular embodiment, the reference distance may be less than 200 meters.

Advantageously, the reference distance may be less than 100 meters.

According to a particular embodiment, the programming interface is an interface for programming by wire.

According to a particular embodiment, the programming interface is an interface for programming by induction.

According to a particular embodiment, the programming interface an interface for programming by radio frequency.

According to a variant, the sub-caliber projectile may comprise an explosive charge, wherein triggering of the explosive charge will ensure breaking of the connection means, and the sub-caliber projectile may also comprise a safety and arming device interposed between the explosive charge and the control means.

The invention also relates to a method of neutralizing a target using such a sub-caliber projectile as well as a weapon system capable of firing the sub-caliber projectile and equipped with a fire control system, wherein the method comprises the following steps:

-   -   a range finding of the target is carried out from the weapon         system equipped with a range finding means;     -   a triggering instant for the breaking of the connection means is         calculated such that breaking occurs at a reference distance         from the target;     -   the timing module of the projectile control means is programmed         with the triggering instant before firing or during firing.

Advantageously, the reference distance is modifiable.

The invention will be better understood on reading the following description of a particular embodiment, description made with reference to the annexed drawings wherein:

FIG. 1 shows the general architecture of a sub-caliber kinetic energy-type projectile;

FIG. 2 is an enlarged view of the rear part of the rod carrying the tail;

FIG. 3a is a schematic of an armored vehicle engaging another armored vehicle;

FIG. 3b is a schematic showing the implementation of the projectile and the method according to the invention.

FIG. 1 shows a kinetic energy projectile 1 which conventionally comprises a sabot 2 made of light material (such as an aluminum alloy), the sabot being formed of several segments and surrounding a sub-caliber rod 3.

The rod is made of steel or a tungsten-based dense alloy.

The rod comprises a conical front part 3 a and carries at its rear part 3 b a tail 4 ensuring its stabilization on trajectory.

The sabot includes a rotating band 5, made of plastic, which ensures the sealing of the propellant gases during firing in the barrel of a weapon (not shown).

During firing, the gases of the propellant charge (not shown) exert their thrust at the rear part 6 of the sabot which is of the same caliber and which constitutes what is called the thrust plate.

Such a general configuration of a sub-caliber tail-stabilized projectile (kinetic energy projectile) is well known. In particular, one may consider patents FR2521717 and FR2661739 which describe known kinetic energy projectiles.

The sabot 2 is intended to allow the projectile to be fired from the weapon. It consists of several segments (most often three) that surround the rod 3 and are in contact one to another at joint planes.

On leaving the barrel of the weapon, the segments of the sabot 2 move away from the rod 3 under the action of the aerodynamic pressure exerted on the front part (AV) of the sabot 2.

The separation of the segments leads to the breaking of the rotating band 5 and the sabot thus releases the rod 3 which continues its trajectory.

Shape-matching means (not shown), for example a thread, are interposed between the sabot 2 and the rod 3 to ensure the driving of the latter.

FIG. 2 shows an enlarged view of the rear part 3 b of the rod 3 carrying the tail 4. The tail 4 comprises a tubular body 4 a on which fins 4 b are fixed fins.

It can be seen that the tail 4 is connected to the rod 3 by a connection means L which is here of the thread/tap type. To this end, the tubular body 4 a of the tail 4 includes a tapped housing 8 which engages on a threaded part 7 of the rod.

The tail body 4 a also contains, behind the tapped housing 8, an explosive charge 9 which can be initiated by a primer (not shown) which is incorporated in a safety and arming device 10.

The safety and arming device 10 is not shown in detail. Such components are conventional and allow pyrotechnic safety during storage and handling of the projectile to be ensured. They ensure a misalignment of the pyrotechnic chain during these phases and provoke the alignment of the chain when the conditions for an effective firing are met.

Given the reduced dimensions of the tubular body 4 a, it is advantageous to produce the safety and arming device 10 using micro-machined technologies. In such devices, the parts are micro-machined or micro-etched on a wafer of a substrate, for example an insulating substrate. This technology, known as MEMS (Micro-Electro-Mechanical System), makes it possible today to produce micro mechanisms by implementing a technique close to that used to produce electronic integrated circuits.

For example, one can consult the patents EP1780495, EP1780496, EP2482027 and EP2482028 which describe such micro-machined security and arming devices.

The safety and arming device 10 is connected to a control means 11 which is an electronic means comprising a timing module 11 a which is programmed before firing or during firing.

The programming can be carried out by means of a programming interface 12 which is housed at the rear of the tail 4 and which is connected to the control means 11, for example by a wire link 13.

The programming interface 12 may be constituted, for example, by a coil allowing remote programming, by induction, when the ammunition is loaded.

Alternatively, the programming interface 12 may be a simple conductive ring which is connected to the base of the ammunition (not shown) by a wire passing through the propellant charge to allow programming by contact once the ammunition is in the weapon chamber.

Finally, the programming interface 12 may be a radio frequency sensor (or an antenna) configured to receive a programming signal by radio (for example in the frequency range of 2 GHz to 5 GHz).

It should be noted that, when the programming interface 12 is inductive or by contact, the programming is done before firing, whereas when the interface 12 is formed by a radio frequency antenna, the programming can be done either before or during firing.

The control means 11 is maintained at a distance from the rear of the tail 4 by a spacer 14. It is possible to provide a tracer T housed behind the spacer 14.

The control means 11 is defined in such a way as to ensure the breaking of the connection means L at a distance, called the reference distance Ref, from the target sought to be neutralized. The breaking is ensured by the triggering of the explosive charge 9. This reference distance depends on the characteristics of the active protection system fitted to the target.

Generally speaking, the reference distance can be chosen to be less than 200 meters and preferably less than 100 meters. But advantageously, this reference distance can be modified to take into account the characteristics of the active protection system of the target encountered, and the reaction time of the protection system could, for example, have been measured by an observer.

The aim is to cause the breaking of the connection means L sufficiently late so that the stabilization of the rod is not disturbed and sufficiently early so that the active protection system cannot act on the rod equipped with its tail.

FIGS. 3a and 3b schematize the mode of operation of the projectile and the method according to the invention.

First of all (FIG. 3a ), a vehicle V1 which wishes to neutralize a target which is in this case a vehicle V2, first carries out a range finding of the vehicle V2, for example by a laser range finder coupled to the fire control system which equips the vehicle V1 (the fire control system is convention and is not shown).

The fire control systems and range finding means are conventional means that equip all combat vehicles equipped with a weapon system S capable of firing sub-caliber projectiles (for example, a smoothbore gun of 120 mm to 140 mm caliber).

The distance Δ between the two vehicles is therefore determined. The fire control system of the vehicle is then able to calculate the time of flight of the rod 3 to the vehicle V2, the ballistic characteristics of the projectile are indeed known and incorporated in firing tables.

The fire control system is capable of determining the instant T2 on trajectory at which the rod 3 will enter a zone Z surrounding the vehicle V2, the zone Z having a radius which is equal to the reference distance Ref chosen by the operator and which can possibly be modified by the latter. Here the reference distance chosen is of the order of 100 meters.

It is this instant T2 which is the triggering instant programmed before firing or during firing in the timing module 11 a.

FIG. 3b shows the rod 3 on trajectory at two different times:

-   -   at instant T1 the rod 3 is on its normal trajectory and it has         its stabilizing tail 4. The safety and arming device 10 is armed         as a result of the firing.     -   at instant T2 the rod 3 enters zone Z. The control means 11         controls the breaking of the connection means L between the rod         3 and the tail 4.

After the breaking of the connection means L, the rod 3 continues its trajectory to the vehicle V2. The distance that remains to be covered is sufficiently reduced so that there is no destabilization of the rod due to the loss of the tail 4.

The tail 4 then follows its own trajectory and moves away from the rod 3.

The vehicle V2 is equipped with an active defense means D projecting blast grenades. This means is ineffective against the rod 3 without its tail, which thus reaches the vehicle without being deflected and with its maximum perforation capacities. The defense means D will only be effective against the tail 4 alone.

It should be noted that, because of the ejection of the tail, the perforation capacities of the rod are also increased.

It should also be noted that the ejection of the tail is comparable to the ejection of a decoy likely to attract towards it the active defense device D. It is therefore likely that the thermobaric grenades will be projected towards the tail and not towards the rod itself. 

1. A sub-caliber projectile of the kinetic energy type, comprising a perforating rod surrounded by a sabot made of light material and allowing the sub-caliber projectile to be fired from a weapon, the rod being extended by a stabilizing tail, the stabilizing tail being connected to the rod by a connection means which can be broken, breaking of the connection means being initiated by a control means integral with the sub-caliber projectile, wherein the control means comprises a timing module which is connected to a programming interface and which is programmed before firing or during firing so as to ensure breaking of the connection means at a reference distance relative to a target which is to be neutralized.
 2. The sub-caliber projectile according to claim 1, wherein the reference distance is less than 200 meters.
 3. The sub-caliber projectile according to claim 2, wherein the reference distance is less than 100 meters.
 4. The sub-caliber projectile according to claim 1, wherein the programming interface is an interface for programming by wire.
 5. The sub-caliber projectile according to claim 1, wherein the programming interface is an interface for programming by induction.
 6. The sub-caliber projectile according to claim 1, wherein the programming interface is an interface for programming by radio frequency.
 7. The sub-caliber projectile according to claim 1, wherein the sub-caliber projectile comprises an explosive charge, wherein triggering of the explosive charge ensures breaking of the connection means, and wherein the sub-caliber projectile comprises a safety and arming device interposed between the explosive charge and the control means.
 8. A method of neutralizing a target using a sub-caliber projectile according to claim 1 as well as a weapon system capable of firing the sub-caliber projectile and equipped with a fire control system, wherein the method comprises the following steps: a range finding of the target is carried out from the weapon system equipped with a range finding means; a triggering instant for breaking of the connection means is calculated such that breaking occurs at a reference distance from the target; the timing module of the projectile control means is programmed with the triggering instant before firing or during firing.
 9. A method of neutralizing a target according to claim 8, wherein the reference distance is modifiable. 